libpthread/nptl/sysdeps/i386/tls.h

   1 /* Definition for thread-local data handling.  nptl/i386 version.
   2    Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _TLS_H
  21 #define _TLS_H  1
  22
  23 #ifndef __ASSEMBLER__
  24 # include <stdbool.h>
  25 # include <stddef.h>
  26 # include <stdint.h>
  27 # include <stdlib.h>
  28 # include <list.h>
  29
  30
  31 /* Type for the dtv.  */
  32 typedef union dtv
  33 {
  34   size_t counter;
  35   struct
  36   {
  37     void *val;
  38     bool is_static;
  39   } pointer;
  40 } dtv_t;
  41
  42
  43 typedef struct
  44 {
  45   void *tcb;            /* Pointer to the TCB.  Not necessarily the
  46                            thread descriptor used by libpthread.  */
  47   dtv_t *dtv;
  48   void *self;           /* Pointer to the thread descriptor.  */
  49   int multiple_threads;
  50   uintptr_t sysinfo;
  51   uintptr_t stack_guard;
  52 } tcbhead_t;
  53
  54 # define TLS_MULTIPLE_THREADS_IN_TCB 1
  55
  56 #else /* __ASSEMBLER__ */
  57 # include <tcb-offsets.h>
  58 #endif
  59
  60
  61 /* We require TLS support in the tools.  */
  62 #define HAVE_TLS_SUPPORT
  63 #define HAVE___THREAD 1
  64 #define HAVE_TLS_MODEL_ATTRIBUTE 1
  65
  66 /* Signal that TLS support is available.  */
  67 #define USE_TLS 1
  68
  69 /* Alignment requirement for the stack.  For IA-32 this is governed by
  70    the SSE memory functions.  */
  71 #define STACK_ALIGN     16
  72
  73 #ifndef __ASSEMBLER__
  74 /* Get system call information.  */
  75 # include <sysdep.h>
  76
  77 /* The old way: using LDT.  */
  78
  79 /* Structure passed to `modify_ldt', 'set_thread_area', and 'clone' calls.  */
  80 struct user_desc
  81 {
  82   unsigned int entry_number;
  83   unsigned long int base_addr;
  84   unsigned int limit;
  85   unsigned int seg_32bit:1;
  86   unsigned int contents:2;
  87   unsigned int read_exec_only:1;
  88   unsigned int limit_in_pages:1;
  89   unsigned int seg_not_present:1;
  90   unsigned int useable:1;
  91   unsigned int empty:25;
  92 };
  93
  94 /* Initializing bit fields is slow.  We speed it up by using a union.  */
  95 union user_desc_init
  96 {
  97   struct user_desc desc;
  98   unsigned int vals[4];
  99 };
 100
 101
 102 /* This is the size of the initial TCB.  Can't be just sizeof (tcbhead_t),
 103    because NPTL getpid, __libc_alloca_cutoff etc. need (almost) the whole
 104    struct pthread even when not linked with -lpthread.  */
 105 # define TLS_INIT_TCB_SIZE sizeof (struct pthread)
 106
 107 /* Alignment requirements for the initial TCB.  */
 108 # define TLS_INIT_TCB_ALIGN __alignof__ (struct pthread)
 109
 110 /* This is the size of the TCB.  */
 111 # define TLS_TCB_SIZE sizeof (struct pthread)
 112
 113 /* Alignment requirements for the TCB.  */
 114 # define TLS_TCB_ALIGN __alignof__ (struct pthread)
 115
 116 /* Get the thread descriptor definition. */
 117 #include <descr.h>
 118
 119 /* The TCB can have any size and the memory following the address the
 120    thread pointer points to is unspecified.  Allocate the TCB there.  */
 121 # define TLS_TCB_AT_TP  1
 122
 123
 124 /* Install the dtv pointer.  The pointer passed is to the element with
 125    index -1 which contain the length.  */
 126 # define INSTALL_DTV(descr, dtvp) \
 127   ((tcbhead_t *) (descr))->dtv = (dtvp) + 1
 128
 129 /* Install new dtv for current thread.  */
 130 # define INSTALL_NEW_DTV(dtvp) \
 131   ({ struct pthread *__pd;                                                    \
 132      THREAD_SETMEM (__pd, header.dtv, (dtvp)); })
 133
 134 /* Return dtv of given thread descriptor.  */
 135 # define GET_DTV(descr) \
 136   (((tcbhead_t *) (descr))->dtv)
 137
 138 #define THREAD_SELF_SYSINFO     THREAD_GETMEM (THREAD_SELF, header.sysinfo)
 139 #define THREAD_SYSINFO(pd)      ((pd)->header.sysinfo)
 140
 141 /* Macros to load from and store into segment registers.  */
 142 # ifndef TLS_GET_GS
 143 #  define TLS_GET_GS() \
 144   ({ int __seg; __asm__ ("movw %%gs, %w0" : "=q" (__seg)); __seg & 0xffff; })
 145 # endif
 146 # ifndef TLS_SET_GS
 147 #  define TLS_SET_GS(val) \
 148   __asm__ ("movw %w0, %%gs" :: "q" (val))
 149 # endif
 150
 151
 152 # ifndef __NR_set_thread_area
 153 #  define __NR_set_thread_area 243
 154 # endif
 155 # ifndef TLS_FLAG_WRITABLE
 156 #  define TLS_FLAG_WRITABLE             0x00000001
 157 # endif
 158
 159 // XXX Enable for the real world.
 160 #if 0
 161 # ifndef __ASSUME_SET_THREAD_AREA
 162 #  error "we need set_thread_area"
 163 # endif
 164 #endif
 165
 166 # ifdef __PIC__
 167 #  define TLS_EBX_ARG "r"
 168 #  define TLS_LOAD_EBX "xchgl %3, %%ebx\n\t"
 169 # else
 170 #  define TLS_EBX_ARG "b"
 171 #  define TLS_LOAD_EBX
 172 # endif
 173
 174 #if defined NEED_DL_SYSINFO
 175 # define INIT_SYSINFO \
 176   _head->sysinfo = GLRO(dl_sysinfo)
 177 #else
 178 # define INIT_SYSINFO
 179 #endif
 180
 181 #ifndef LOCK_PREFIX
 182 # ifdef UP
 183 #  define LOCK_PREFIX  /* nothing */
 184 # else
 185 #  define LOCK_PREFIX "lock;"
 186 # endif
 187 #endif
 188
 189 /* Code to initially initialize the thread pointer.  This might need
 190    special attention since 'errno' is not yet available and if the
 191    operation can cause a failure 'errno' must not be touched.  */
 192 # define TLS_INIT_TP(thrdescr, secondcall) \
 193   ({ void *_thrdescr = (thrdescr);                                            \
 194      tcbhead_t *_head = _thrdescr;                                            \
 195      union user_desc_init _segdescr;                                          \
 196      int _result;                                                             \
 197                                                                               \
 198      _head->tcb = _thrdescr;                                                  \
 199      /* For now the thread descriptor is at the same address.  */             \
 200      _head->self = _thrdescr;                                                 \
 201      /* New syscall handling support.  */                                     \
 202      INIT_SYSINFO;                                                            \
 203                                                                               \
 204      /* The 'entry_number' field.  Let the kernel pick a value.  */           \
 205      if (secondcall)                                                          \
 206        _segdescr.vals[0] = TLS_GET_GS () >> 3;                                \
 207      else                                                                     \
 208        _segdescr.vals[0] = -1;                                                \
 209      /* The 'base_addr' field.  Pointer to the TCB.  */                       \
 210      _segdescr.vals[1] = (unsigned long int) _thrdescr;                       \
 211      /* The 'limit' field.  We use 4GB which is 0xfffff pages.  */            \
 212      _segdescr.vals[2] = 0xfffff;                                             \
 213      /* Collapsed value of the bitfield:                                      \
 214           .seg_32bit = 1                                                      \
 215           .contents = 0                                                       \
 216           .read_exec_only = 0                                                 \
 217           .limit_in_pages = 1                                                 \
 218           .seg_not_present = 0                                                \
 219           .useable = 1 */                                                     \
 220      _segdescr.vals[3] = 0x51;                                                \
 221                                                                               \
 222      /* Install the TLS.  */                                                  \
 223      __asm__ volatile (TLS_LOAD_EBX                                           \
 224                    "int $0x80\n\t"                                            \
 225                    TLS_LOAD_EBX                                               \
 226                    : "=a" (_result), "=m" (_segdescr.desc.entry_number)       \
 227                    : "0" (__NR_set_thread_area),                              \
 228                      TLS_EBX_ARG (&_segdescr.desc), "m" (_segdescr.desc));    \
 229                                                                               \
 230      if (_result == 0)                                                        \
 231        /* We know the index in the GDT, now load the segment register.        \
 232           The use of the GDT is described by the value 3 in the lower         \
 233           three bits of the segment descriptor value.                         \
 234                                                                               \
 235           Note that we have to do this even if the numeric value of           \
 236           the descriptor does not change.  Loading the segment register       \
 237           causes the segment information from the GDT to be loaded            \
 238           which is necessary since we have changed it.   */                   \
 239        TLS_SET_GS (_segdescr.desc.entry_number * 8 + 3);                      \
 240                                                                               \
 241      _result == 0 ? NULL                                                      \
 242      : "set_thread_area failed when setting up thread-local storage\n"; })
 243
 244
 245 /* Return the address of the dtv for the current thread.  */
 246 # define THREAD_DTV() \
 247   ({ struct pthread *__pd;                                                    \
 248      THREAD_GETMEM (__pd, header.dtv); })
 249
 250
 251 /* Return the thread descriptor for the current thread.
 252
 253    The contained asm must *not* be marked volatile since otherwise
 254    assignments like
 255         pthread_descr self = thread_self();
 256    do not get optimized away.  */
 257 # define THREAD_SELF \
 258   ({ struct pthread *__self;                                                  \
 259      __asm__ ("movl %%gs:%c1,%0" : "=r" (__self)                              \
 260           : "i" (offsetof (struct pthread, header.self)));                    \
 261      __self;})
 262
 263 /* Magic for libthread_db to know how to do THREAD_SELF.  */
 264 # define DB_THREAD_SELF \
 265   REGISTER_THREAD_AREA (32, offsetof (struct user_regs_struct, xgs), 3) \
 266   REGISTER_THREAD_AREA (64, 26 * 8, 3) /* x86-64's user_regs_struct->gs */
 267
 268
 269 /* Read member of the thread descriptor directly.  */
 270 # define THREAD_GETMEM(descr, member) \
 271   ({ __typeof (descr->member) __value;                                        \
 272      if (sizeof (__value) == 1)                                               \
 273        __asm__ volatile ("movb %%gs:%P2,%b0"                                  \
 274                      : "=q" (__value)                                         \
 275                      : "0" (0), "i" (offsetof (struct pthread, member)));     \
 276      else if (sizeof (__value) == 4)                                          \
 277        __asm__ volatile ("movl %%gs:%P1,%0"                                   \
 278                      : "=r" (__value)                                         \
 279                      : "i" (offsetof (struct pthread, member)));              \
 280      else                                                                     \
 281        {                                                                      \
 282          if (sizeof (__value) != 8)                                           \
 283            /* There should not be any value with a size other than 1,         \
 284               4 or 8.  */                                                     \
 285            abort ();                                                          \
 286                                                                               \
 287          __asm__ volatile ("movl %%gs:%P1,%%eax\n\t"                          \
 288                        "movl %%gs:%P2,%%edx"                                  \
 289                        : "=A" (__value)                                       \
 290                        : "i" (offsetof (struct pthread, member)),             \
 291                          "i" (offsetof (struct pthread, member) + 4));        \
 292        }                                                                      \
 293      __value; })
 294
 295
 296 /* Same as THREAD_GETMEM, but the member offset can be non-constant.  */
 297 # define THREAD_GETMEM_NC(descr, member, idx) \
 298   ({ __typeof (descr->member[0]) __value;                                     \
 299      if (sizeof (__value) == 1)                                               \
 300        __asm__ volatile ("movb %%gs:%P2(%3),%b0"                              \
 301                      : "=q" (__value)                                         \
 302                      : "0" (0), "i" (offsetof (struct pthread, member[0])),   \
 303                      "r" (idx));                                              \
 304      else if (sizeof (__value) == 4)                                          \
 305        __asm__ volatile ("movl %%gs:%P1(,%2,4),%0"                            \
 306                      : "=r" (__value)                                         \
 307                      : "i" (offsetof (struct pthread, member[0])),            \
 308                        "r" (idx));                                            \
 309      else                                                                     \
 310        {                                                                      \
 311          if (sizeof (__value) != 8)                                           \
 312            /* There should not be any value with a size other than 1,         \
 313               4 or 8.  */                                                     \
 314            abort ();                                                          \
 315                                                                               \
 316          __asm__ volatile  ("movl %%gs:%P1(,%2,8),%%eax\n\t"                  \
 317                         "movl %%gs:4+%P1(,%2,8),%%edx"                        \
 318                         : "=&A" (__value)                                     \
 319                         : "i" (offsetof (struct pthread, member[0])),         \
 320                           "r" (idx));                                         \
 321        }                                                                      \
 322      __value; })
 323
 324
 325 /* Same as THREAD_SETMEM, but the member offset can be non-constant.  */
 326 # define THREAD_SETMEM(descr, member, value) \
 327   ({ if (sizeof (descr->member) == 1)                                         \
 328        __asm__ volatile ("movb %b0,%%gs:%P1" :                                \
 329                      : "iq" (value),                                          \
 330                        "i" (offsetof (struct pthread, member)));              \
 331      else if (sizeof (descr->member) == 4)                                    \
 332        __asm__ volatile ("movl %0,%%gs:%P1" :                                 \
 333                      : "ir" (value),                                          \
 334                        "i" (offsetof (struct pthread, member)));              \
 335      else                                                                     \
 336        {                                                                      \
 337          if (sizeof (descr->member) != 8)                                     \
 338            /* There should not be any value with a size other than 1,         \
 339               4 or 8.  */                                                     \
 340            abort ();                                                          \
 341                                                                               \
 342          __asm__ volatile ("movl %%eax,%%gs:%P1\n\t"                          \
 343                        "movl %%edx,%%gs:%P2" :                                \
 344                        : "A" (value),                                         \
 345                          "i" (offsetof (struct pthread, member)),             \
 346                          "i" (offsetof (struct pthread, member) + 4));        \
 347        }})
 348
 349
 350 /* Set member of the thread descriptor directly.  */
 351 # define THREAD_SETMEM_NC(descr, member, idx, value) \
 352   ({ if (sizeof (descr->member[0]) == 1)                                      \
 353        __asm__ volatile ("movb %b0,%%gs:%P1(%2)" :                            \
 354                      : "iq" (value),                                          \
 355                        "i" (offsetof (struct pthread, member)),               \
 356                        "r" (idx));                                            \
 357      else if (sizeof (descr->member[0]) == 4)                                 \
 358        __asm__ volatile ("movl %0,%%gs:%P1(,%2,4)" :                          \
 359                      : "ir" (value),                                          \
 360                        "i" (offsetof (struct pthread, member)),               \
 361                        "r" (idx));                                            \
 362      else                                                                     \
 363        {                                                                      \
 364          if (sizeof (descr->member[0]) != 8)                                  \
 365            /* There should not be any value with a size other than 1,         \
 366               4 or 8.  */                                                     \
 367            abort ();                                                          \
 368                                                                               \
 369          __asm__ volatile ("movl %%eax,%%gs:%P1(,%2,8)\n\t"                   \
 370                        "movl %%edx,%%gs:4+%P1(,%2,8)" :                       \
 371                        : "A" (value),                                         \
 372                          "i" (offsetof (struct pthread, member)),             \
 373                          "r" (idx));                                          \
 374        }})
 375
 376
 377 /* Atomic compare and exchange on TLS, returning old value.  */
 378 #define THREAD_ATOMIC_CMPXCHG_VAL(descr, member, newval, oldval) \
 379   ({ __typeof (descr->member) __ret;                                          \
 380      __typeof (oldval) __old = (oldval);                                      \
 381      if (sizeof (descr->member) == 4)                                         \
 382        __asm__ volatile (LOCK_PREFIX "cmpxchgl %2, %%gs:%P3"                  \
 383                      : "=a" (__ret)                                           \
 384                      : "0" (__old), "r" (newval),                             \
 385                        "i" (offsetof (struct pthread, member)));              \
 386      else                                                                     \
 387        /* Not necessary for other sizes in the moment.  */                    \
 388        abort ();                                                              \
 389      __ret; })
 390
 391
 392 /* Atomic set bit.  */
 393 #define THREAD_ATOMIC_BIT_SET(descr, member, bit) \
 394   (void) ({ if (sizeof ((descr)->member) == 4)                                \
 395               __asm__ volatile (LOCK_PREFIX "orl %1, %%gs:%P0"                \
 396                             :: "i" (offsetof (struct pthread, member)),       \
 397                                "ir" (1 << (bit)));                            \
 398             else                                                              \
 399               /* Not necessary for other sizes in the moment.  */             \
 400               abort (); })
 401
 402
 403 /* Call the user-provided thread function.  */
 404 #define CALL_THREAD_FCT(descr) \
 405   ({ void *__res;                                                             \
 406      int __ignore1, __ignore2;                                                \
 407      __asm__ volatile ("pushl %%eax\n\t"                                              \
 408                    "pushl %%eax\n\t"                                          \
 409                    "pushl %%eax\n\t"                                          \
 410                    "pushl %%gs:%P4\n\t"                                       \
 411                    "call *%%gs:%P3\n\t"                                       \
 412                    "addl $16, %%esp"                                          \
 413                    : "=a" (__res), "=c" (__ignore1), "=d" (__ignore2)         \
 414                    : "i" (offsetof (struct pthread, start_routine)),          \
 415                      "i" (offsetof (struct pthread, arg)));                   \
 416      __res; })
 417
 418
 419 /* Set the stack guard field in TCB head.  */
 420 #define THREAD_SET_STACK_GUARD(value) \
 421   THREAD_SETMEM (THREAD_SELF, header.stack_guard, value)
 422 #define THREAD_COPY_STACK_GUARD(descr) \
 423   ((descr)->header.stack_guard                                                \
 424    = THREAD_GETMEM (THREAD_SELF, header.stack_guard))
 425
 426
 427 #endif /* __ASSEMBLER__ */
 428
 429 #endif  /* tls.h */